Spidey and Iron Man: Avengers Team Up!

The movie is a fine special for the spidey and friend's tv show. But I just couldn't help thinking how they could have improved so many things or how certain plot points didn't make sense. Why didn't the green goblin use the robot controller machine to take control of Ultron the moment he got his hands on it? Why didn't they account for the combined strength of the team when making the cage? They should have made it heavier or attached it to the floor or something. How would Ultron even eat a churro? Why does black Panther have a British accent?

Also for a special called "Spidey and Iron Man: Avengers Team-Up!" the avengers do very little for the story, it's basically just spider-man and iron man for 90% of the film, the rest of the time the avengers are off screen, or not really contributing or just being stuck in the cage. Just really think they should have had more interactions with each other.